Pump or the like



Spt. 17, 1963 c, MCFARLAND 3,103,892

PUMP OR THE LIKE Filed Nov. 21, 1960 2 Sheets-Sheet 1 FIG. I.

F|G.2. FlG.3.

INVENTOR. CHESTER R. McFARLAND dwjyp ATTORNEY Sept. 17, 1963 c. R.MOFARLAND 3,103,892

' PUMP OR THE LIKE 4 Filed Nov. 21, 1960 2 Sheets-Sheet 2 INVENTOR.CHESTER R. Mc FARLAND I ATIOR NEYS 3,103,892 PUMP QR THE LIKE ChesterlR. McFariand, Hightstown, NJL, assignor, by mesne assignments, to DeLaval Turbine inc, Trenton, Ni, a corporation of Delaware Filed Nov. 21,1%0, Ser. No. 70,476 1 Claim. (Cl. 103-108) This invention relates topumps, compressors, or the like, and has particular reference to suchmachines having multiple stages and of the so-called barrel type.

Reference will be particularly made to liquid centrifugal pumps of thetype involving delivery of liquid at high pressure. For this purpose,there are commonly provided pumps of the barrel type in which rotaryimpellers carried by a common shaft are assembled with a casing made upof disc-like stage elements which are stacked together. This assembly isthen located in an outer housing capable of withstanding the pressuregradients, the stacked elements being held together primarily by thepressure gradient between outlet and inlet. This construction is incontrast with centrifugal pumps in which all of the passage-definingparts, or the majority of them, are provided in the halves of a casingsplit axially.

In the case of barrel pumps a manufacturer is frequently called upon tomeet specifications for deliveries and pressures which call for variousnumbers of stages and different size impellers, but which specificationsmay be met by casings of the same diameter. It is a general object ofthe present invention to provide a pump construction requiring, for asingle pump, duplicate parts, and for pumps for different capacities anddelivery pressures parts which may be similar except for minordimensional differences readily achieved by machining of castings. Inbrief, the invention contemplates the provision of a wide variety ofpumps producible from the same interstage diaphragms and diffuserassemblies merely by simple turning of standard castings. While theinvention is particularly applicable to pumps presenting the variableproblems indicated above, it will become evident that the invention isalso applicable to centrifugal compressors, turbines, or the like.

The foregoing general object as well as subsidiary objects relating todetails of construction and arrangement will become apparent from thefollowing description read in conjunction with the accompanying drawingsin which:

FIGURE 1 is an axial section showing the pertinent parts of a pumpconstructed in accordance with the invention;

FlGURE 2 is an elevation of a diffuser element located between thedischarge of one impeller and the entrance to a subsequent one;

FIGURE 3 is an elevation side of FIGURE 2;

FIGURES 4 and 5 are diagrams illustrating the assemblies of interstagediaphragms provided in accordance with the invention; and

FIGURE 6 is a diagram illustrating the form taken by a standard castingfrom which interstage diaphragms may be readily produced by machining.

Referring first to FIGURE 1, the pump shown is of the barrel type, andexcept for the parts specially provided in accordance with the inventionhas a generally conventional structure and operates in conventionalfashion. An outer housing 2 is provided having a generally cylindricalform and designed to withstand the pressures involved. This housing isprovided with an inlet passage at 4 and a discharge passage at 6. Thehousing is provided at its left-hand end with a shoulder 7 against whichthe casing assembly abuts under the high discharge pressure. At itsright-hand end the housing is provided with looking at the right-hand aconventional closure '8, Whlh houses conventional packing and bearingarrangements which are not illustrated. At the left-hand end of thehousing there is the bearing assembly generally indicated at 10. Theinvention is concerned primarily with the barrel assembly within thehuosing and details of the housing and otherstructures are not involvedand are therefore not shown in detail. It need only be remarked thatfor'pumps of different lengths (i.e. different numbers of stages)different housing 2 will be provided, though the associated endclosures, bearings, etc., may be standard for different size pumps. 7

The casing which is located within the housing ismade up of stackedelements "comprising the end element 12, the duplicate interstagediaphragms 14, and the outlet element 16. Concentric stacked arrangementof these elements in maintained by interlocking 'rabbets as will beevident from FIGURE 1. Nested'in the interstage diaphragms 1d arediffuser elements 18 secured bybolts 19. A shaft 20 has mounted thereonin conventional fashion the various impellers 22 of the stages involved,these being provided with the usual vanes. For pumps of differentcapacities these impellers will, in general, be different in the senseof having wider or narrower passages between the vanes; but in anyindividual multistage pump the impellers will generally be identical inusual pumps. In the case of pumps of different capacities, despite thedifferences of the impeller passages the impellers -will usually be thesame in'their structural relationship to the shaft and the interstagedimensions will be the same. Consequently, the same shaft may be usedfor pumps to the same number of stages but of different capacities,assuming, of course, that radial dimensions involved are substantiallythe same. While the generally very high pressure drop between outlet andinlet will maintain the assembly, it is desirable in the assemblyoperation to hold the interstage diaphragms together in final stackedrelationship, and for this purpose tie elements 24 are used as describedin the application f0 Karol Pilarczyk, Serial No. 130,988, filed August1 1, 1961.

Considering the already described aspects of duplications of parts forpumps to different capacities and numbers of stages, the inventionprovides simplification in the :matter of minimizing the variety ofelements to be used by special forms and assemblies particularly of theinterstage diaphragms and the diffuser assemblies or elements. l

The type of diffuser element provided in accordance With the inventionis illustrated in greater detail in FIG- URES 2 and 3. This diffuserelement .18 comprises a cast disc which is of small axial extent exceptat its peripheral portions. It comprises diffuser vanes on the sidefacing the discharge of one impeller, cross-over passages for the liquidbeing pumped, and return passages and guide vanes on its opposite sidearranged to direct the flow to the inlet of the next subsequent stageimpeller.

The relatively thin central portion of this element is indicated at 21.Adjacent the periphery there are provided the diffuser vanes 23 whichspiral outwardly from their inlet edges 25. On the opposite side of thedisc there are the return vanes 27 which spiral inwardly from theirinlet edges at 26 to their outlet edges at .23. As will be evident fromFIGURE 3, in particular, cross-over passages 30 exist at the peripheryof the element 18 to carry the liquid from one side to the other of thecentral portion 21. Closer to the shaft there are provided theredirecting vanes 36 to turn the inwardly spiraling flow substantiallyradially for entrance into the eye of the next stage impeller withoutsubstantial spin.

Consideration of the construction just described will Patented Sept.'17, reefs,

re eal that starting with an ample width between the generally radialfaces 32 and 34 of this construction a simple turning procedure carriedout on a lathe may be used to form diffuser elements of different widthsas to both entrance and exit passages. As will become clearer from thefollowing consideration of the inter-stage diaphragms, this results inextreme case of adaption of a single standard type of casting to producethe diffuser elements for pumps of different capacities, in particularto fit them to impellers of different sizes.

Reference may now be made to FIGURES 4 and 5 showing the assemblyarrangement of interstage diaphragms, two adjacent ones of which areillustrated. In the arrangement illustrated in FIGURE 4, thesediaphragms are arranged to provide a minimum of axial space for thediffuser elements, the space 40 having the typical dimension A (Thespace, as indicated, may involve both radial and conical wall portions;but the dimension ,A may be regarded as typical). Still referring toFIGURE 4, a typical wall thickness dimension is indicated at B From thefact that these typical dimensions are taken between radial wallportions, it will be evident that the interstage dimension,i.e. thespace of similar parts of the impellers and the other repetitiveelements will be A +B On the other hand, considering FIGURE 5, the space40 is here indicated as the maximum space that may be desired in thecase of a larger capacity impeller with a correspondingly axially widerdiffuser element. The space dimension A is now greater. The walldimension B, for the interstage diaphragms is now such that A +B isequal to Ari-B The interstage spacing is thus constant.

Considering, now, FIGURE 6, the outside outline of this indicates theshape of a casting 14A from which both the extreme size diaphragms 14and 14' may be produced by simple turning. To provide a diaphragm suchas 14 of maximum wall thickness the shaded portion 42 may be removed. Onthe other hand to produce the diaphragm of minimum wall thickness theshaded portion 44 may be removed. Itwill also be obvious that from thissame casting 14A machining may produce any diaphragm of intermediatewall thickness by partial removals of material at both the right andleft. (The original casting may, of course, be provided with excessmaterial such as indicated at 46 to provide for proper finishmachining.)

As will now be evident, the amply sized casting 14A and a casting forthe diffuser element having an ample dimension between the faces 32 and34 will sufiice for the construction and assemblage of pumps havingdifferent size impellers and/or different numbers of stages. When theproper machining is accomplished to remove excess material, the diffuserelements will rest Within and may be secured in the cups formed withinthe interstage diaphragms, securing being achieved by bolts as indicatedat 19. The stacking of the interstage diaphragms will then result in theestablishment of standard spacing for the various repetitive elements,including the impellers, along the shaft. The result is a completelysatisfactory construction from the standpoint of operation with greatlysimplified aspects of production of parts and their stock piling to meetthe demands of various orders for pumps.

It will be evident from the foregoing that the inventionis equallyapplicable to other rotary machines such as compressors and turbines. Inthe case of compressors the successive stage impellers are generally ofdifferent size; and in such case, of course, the interstage diaphragmsand the diffuser elements may also successively change in size fromstageto stage. But in accordance with the invention these latterelements may also be machined, by turning, from the same standardcastings.

In the case of turbines of gas or liquid types, discs similar to thediffuser elements of the pumps will carry vanes on one or both sides todefine diffusers (which may, of course, be vaneless) and nozzles as wellas redirecting vanes, all to provide gas or liquid passages functioningconventionally but structurally having the advantages of the invention.

It will, therefore, be clear that various changes may be made inaccordance with the invention, adapting it to different rotary fluidhandling devices, without departing from the scope thereof as defined inthe following claim.

What is claimed is:

A multistage pump or the like comprising a rotary shaft, axially spacedvaned rotors carried by the shaft, a housing for said shaft and rotors,said housing comprising coaxially stacked peripherally abuttinginterstage diaphragms, one for each rotor, each of integral, vanelessand cup-shaped form, i.e., having a radially directed portion throughwhich said shaft extends centrally and an outer peripheral portionprojecting therefrom at one side of said radially directed portion, anddisc-shaped elements in the spaces within each of said respectivecup-shaped diaphragms, each of said elements comprising a radialportion, diffuser vanes integral with said radial portion, extendingaxially from said radial portion in one direction and spirallingoutwardly, return vanes integral with said radial portion, extendingaxially from said radial portion in the opposite direction andspiralling inwardly, and redirecting vanes integral with said radialportion extending axially from said radial portion in the last mentioneddirection and spiralling inwardly, said elements providing helicalcross-over passages between said diffuser vanes and return vanes, andeach of said elements having all of its respective vanes terminatingaxially substantially at the radially directed portions of saiddiaphragms, and each of said elements presenting outwardly extendedcylindrical portions between said cross-over passages, all of saiddiaphragms having substantially identical radial extents of their parts,and all of said elements having substantially identical radial extentsof their parts, with said diaphragms and elements alone defining theflow passages from each rotor to that of the next succeeding stage, anda casing surrounding the diaphragms and separated from said elements bysaid stacked diaphragms.

References Cited in the file of this patent UNITED STATES PATENTS2,620,553 Schultz Dec. 9, 1952 2,786,261 Schalyo Mar. 26, 1957 2,954,739Lung Oct. 4, 1960 FOREIGN PATENTS 17,283 Great Britain of 1915 62,273Austria Nov. 25, 1913 77,715 Holland May 16, 1955 123,153 Australia Jan.16, 1947 221,387 Switzerland Aug. 17, 1942 550,901 Italy Nov. 14, 1956785,419 Great Britain Oct. 30, 1957 826,569 Great Britain Jan. 13, 1960

